A triode-for-alternating-current (TRIAC) dimmer may be achieved merely by a TRIAC thyristor, and as compared with the other dimmers, it is simple and cheap, so it has been widely used nowadays.
In the case that an LED lamp is used to replace an incandescent lamp for illumination, it is necessary to provide a peripheral circuit capable of being compatible with the TRIAC dimmer.
However, the conventional peripheral circuit suitable for the TRIAC dimmer has a complex structure and low conversion efficiency. In addition, there are issues of dimming performances, such as bad dimming linearity, narrow dimming range and flickering.